On 9/26/23 12:56, Joern Rennecke wrote:
What ultimately pushed us to keep moving forward on this effort was
discovering numerous CRC loop implementations out in the wild, including
4 implementations (IIRC) in the kernel itself.
I have always assumed that such must exist (CRCs are useful f
On Tue, 26 Sept 2023 at 14:18, Jeff Law wrote:
> But the Coremark code is what it is. This isn't a whole lot
> different than the work in the 90s which rewrote loops and compromised
> some of the spec benchmarks, or the eqntott hack to simplify that one
> key loop in eqntott.
I think the state
On Tue, 26 Sep 2023, Jeff Law wrote:
> What ultimately pushed us to keep moving forward on this effort was
> discovering numerous CRC loop implementations out in the wild, including 4
> implementations (IIRC) in the kernel itself.
The kernel employs bitwise CRC only in look-up table generators.
On 9/23/23 17:05, Joern Rennecke wrote:
Mariam Harutyunyan:
+++ b/gcc/ChangeLog
@@ -1,3 +1,45 @@
+2023-08-03 Mariam Arutunian
+
It is common courtesy to include all authors in the list of authors
for the ChangeLog; also,
this may help people in the future understand the history of the code
On Sun, 2023-09-24 at 00:05 +0100, Joern Rennecke wrote:
>
> Although maybe Oleg Endo's library, as mentioned in
> https://gcc.gnu.org/pipermail/gcc-patches/2022-March/591748.html ,
> might be suitable? What is the license for that?
>
>
I haven't published the library, but I think I could do t
On Sun, Sep 24, 2023, 00:05 Joern Rennecke
wrote:
> Mariam Harutyunyan:
> +++ b/gcc/ChangeLog
> @@ -1,3 +1,45 @@
> +2023-08-03 Mariam Arutunian
> +
>
> It is common courtesy to include all authors in the list of authors
> for the ChangeLog; also,
> this may help people in the future understand
On Sun, 24 Sept 2023 at 12:41, Alexander Monakov wrote:
>
>
> On Sun, 24 Sep 2023, Joern Rennecke wrote:
>
> > It is a stated goal of coremark to test performance for CRC.
>
> I would expect a good CRC benchmark to print CRC throughput in
> bytes per cycle or megabytes per second.
>
> I don't see
On Sun, 24 Sep 2023, Joern Rennecke wrote:
> It is a stated goal of coremark to test performance for CRC.
I would expect a good CRC benchmark to print CRC throughput in
bytes per cycle or megabytes per second.
I don't see where Coremark states that goal. In the readme at
https://github.com/eem
Mariam Harutyunyan:
+++ b/gcc/ChangeLog
@@ -1,3 +1,45 @@
+2023-08-03 Mariam Arutunian
+
It is common courtesy to include all authors in the list of authors
for the ChangeLog; also,
this may help people in the future understand the history of the code better.
While must of your patch is new, it
Thank you for the review.
I'm already working on suggested changes.
The answers to the few questions are attached here.
Thanks,
Mariam
On Wed, Aug 16, 2023 at 8:59 AM Jeff Law wrote:
>
>
> On 8/3/23 13:37, Mariam Harutyunyan via Gcc-patches wrote:
> > This patch adds CRC support for the RISC-V
On Wed, 16 Aug 2023, Philipp Tomsich wrote:
> > > I fully expect that latency to drop within the next 12-18 months. In that
> > > world, there's not going to be much benefit to using hand-coded libraries
> > > vs
> > > just letting the compiler do it.
>
> I would also hope that the hand-coded
On 8/16/23 13:10, Alexander Monakov wrote:
On Tue, 15 Aug 2023, Jeff Law wrote:
Because if the compiler can optimize it automatically, then the projects have
to do literally nothing to take advantage of it. They just compile normally
and their bitwise CRC gets optimized down to either a ta
> On Aug 16, 2023, at 3:42 PM, Philipp Tomsich wrote:
>
> On Wed, 16 Aug 2023 at 21:10, Alexander Monakov wrote:
>>
>>
>> On Tue, 15 Aug 2023, Jeff Law wrote:
>>
>>> Because if the compiler can optimize it automatically, then the projects
>>> have
>>> to do literally nothing to take advan
On Wed, 16 Aug 2023 at 21:10, Alexander Monakov wrote:
>
>
> On Tue, 15 Aug 2023, Jeff Law wrote:
>
> > Because if the compiler can optimize it automatically, then the projects
> > have
> > to do literally nothing to take advantage of it. They just compile normally
> > and their bitwise CRC gets
On Tue, 15 Aug 2023, Jeff Law wrote:
> Because if the compiler can optimize it automatically, then the projects have
> to do literally nothing to take advantage of it. They just compile normally
> and their bitwise CRC gets optimized down to either a table lookup or a clmul
> variant. That's t
On 8/3/23 13:37, Mariam Harutyunyan via Gcc-patches wrote:
This patch adds CRC support for the RISC-V architecture. It adds internal
functions and built-ins specifically designed to handle CRC computations
efficiently.
If the target is ZBC, the clmul instruction is used for the CRC code
genera
On 8/9/23 07:02, Paul Koning wrote:
On Aug 9, 2023, at 2:32 AM, Alexander Monakov wrote:
On Tue, 8 Aug 2023, Jeff Law wrote:
If the compiler can identify a CRC and collapse it down to a table or clmul,
that's a major win and such code does exist in the real world. That was the
whole po
On 8/9/23 00:32, Alexander Monakov wrote:
On Tue, 8 Aug 2023, Jeff Law wrote:
If the compiler can identify a CRC and collapse it down to a table or clmul,
that's a major win and such code does exist in the real world. That was the
whole point behind the Fedora experiment -- to determine if
> On Aug 9, 2023, at 2:32 AM, Alexander Monakov wrote:
>
>
> On Tue, 8 Aug 2023, Jeff Law wrote:
>
>> If the compiler can identify a CRC and collapse it down to a table or clmul,
>> that's a major win and such code does exist in the real world. That was the
>> whole point behind the Fedora e
On Tue, 8 Aug 2023, Jeff Law wrote:
> If the compiler can identify a CRC and collapse it down to a table or clmul,
> that's a major win and such code does exist in the real world. That was the
> whole point behind the Fedora experiment -- to determine if these things are
> showing up in the real
On 8/8/23 17:31, Andrew Pinski wrote:
On Tue, Aug 8, 2023 at 4:17 PM Jeff Law via Gcc-patches
wrote:
On 8/8/23 10:38, Alexander Monakov wrote:
On Tue, 8 Aug 2023, Jeff Law wrote:
That was my thinking at one time. Then we started looking at the distros and
found enough crc implementat
On Tue, Aug 8, 2023 at 4:17 PM Jeff Law via Gcc-patches
wrote:
>
>
>
> On 8/8/23 10:38, Alexander Monakov wrote:
> >
> > On Tue, 8 Aug 2023, Jeff Law wrote:
> >
> >> That was my thinking at one time. Then we started looking at the distros
> >> and
> >> found enough crc implementations in there t
On 8/8/23 10:38, Alexander Monakov wrote:
On Tue, 8 Aug 2023, Jeff Law wrote:
That was my thinking at one time. Then we started looking at the distros and
found enough crc implementations in there to change my mind about the overall
utility.
The ones I'm familiar with are all table-based
On Tue, 8 Aug 2023, Jeff Law wrote:
> That was my thinking at one time. Then we started looking at the distros and
> found enough crc implementations in there to change my mind about the overall
> utility.
The ones I'm familiar with are all table-based and look impossible to
pattern-match (and
On 8/8/23 09:22, Alexander Monakov wrote:
Jeff, as I understand this all is happening only because Coremark contains
use of bitwise CRC that affects benchmark scores. In another universe where
- Coremark was careful to checksum outputs outside of timed sections, or
- implemented CRC in a man
On Thu, 3 Aug 2023, Jeff Law wrote:
> The end goal here is to actually detect bitwise CRC implementations in the
> gimple optimizers and turn them into table lookups or carryless multiplies in
> RTL.
>
> Mariam has that working end-to-end and has proposed a talk for the Cauldron on
> the topic.
On 8/3/23 13:37, Mariam Harutyunyan via Gcc-patches wrote:
This patch adds CRC support for the RISC-V architecture. It adds internal
functions and built-ins specifically designed to handle CRC computations
efficiently.
If the target is ZBC, the clmul instruction is used for the CRC code
gener
Hi.
Thank you. I'll add.
Best regards,
Mariam
On Thu, Aug 3, 2023, 23:56 Andrew Pinski wrote:
> On Thu, Aug 3, 2023 at 12:38 PM Mariam Harutyunyan via Gcc-patches
> wrote:
> >
> > This patch adds CRC support for the RISC-V architecture. It adds internal
> > functions and built-ins specifically
On Thu, Aug 3, 2023 at 12:38 PM Mariam Harutyunyan via Gcc-patches
wrote:
>
> This patch adds CRC support for the RISC-V architecture. It adds internal
> functions and built-ins specifically designed to handle CRC computations
> efficiently.
>
> If the target is ZBC, the clmul instruction is used
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